Conventionally, automatic transmissions for automatically switching a transmission gear in accordance with the speed of a vehicle (vehicle speed), the accelerator operation by the driver, and the like are used in vehicles such as automobiles.
For example, PTL 1 discloses a transmission control device in which a target transmission gear of an automatic transmission is set based on the vehicle speed and the amount of the accelerator operated by the driver in accordance with a shift map set in advance, and the transmission control of the automatic transmission is performed based on the target transmission gear.
In this transmission control device, when it is determined that an upslope road is included in a predetermined distance range on the course of the vehicle based on the map information, the target transmission gear is set to a transmission gear lower than the present transmission gear of the vehicle traveling on the flat road before the vehicle reaches the upslope road. This configuration aims to avoid degradation of travel feeling due to significant reduction in speed on the upslope road.